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MANUFACTURE or moon Moron rum. HYDROCABBONS Karl Korpi and Arthur B.Goldsby, Beacon, N. Y., assignors to The Texas Company, New York, N. Y.,a corporation of Delaware No Drawing. Original No. 2,260,943, datedomber 28, 1941, Serial No. 150,316, June 25, 1937. Application forreissue March 18,1942, Serial 7 Claims. This invention relates to motorfuels and has to do particularly with the manufacture of antiknock motorfuel hydrocarbons.

Inthe manufacture of iso-octane it is custom ary to polymerize one ormore of the butylenes present in a C4 hydrocarbon fraction to di-.

butylenes and then hydrogenate the di-butylenes to iso-octanes. Thehydrogenation of the dibutylenes to octanes is an expensive operationand requires careful control and costly equipment. We have found thatthese octanes may be produced directly without a hydrogenation step byreacting the olefins with isobutane.

In an unsaturated C4 hydrocarbon fraction, such as cracking still gases,there are usually present besides normal butane, iso-butane, butene-l,butene-2 and iso-butene. The iso- 'butene may be selectively polymerizedto diisobutylene by absorbing the. oleflns in a selective polymerizingcatalyst such as sulfuric acid of about 6070% H2804 concentration, attemperatures of less than about 90 F., and then polymerizing theabsorbed ole ilns by heating to about 200 F. By varying theconcentration and temperatures, or employing less selective activecatalysts, such as phosphoric acid, aluminum chloride, etc.,polymerization of the normal butenes or cross-polymerization between theiso-butene and normal butenes may be eflected to produce isomericoctylenes.

Furthermore, regardless of the source or type of manufacture of thedi-butylenes or octylenes,

we may convert such hydrocarbons from any source to octanes inaccordance with our invention. 1

It is contemplated that in addition to octylene fractions any olefinstock such as polymer naphtha may be converted to saturated products.And while we prefer to use lac-butane as the isoparaflln for thereaction with oleiln stocks, isopentane or a mixture of iso-butane andisopentane may be used. In practicing the invention a cracked C4hydrocarbon fraction containing normal and isobutenes may be treatedwith sulfuric acidof about 60-70% H2804 concentration at a temperatureof about 80-90 F. to selectively absorb the tertiary oleiins. Thesolution of sulfuric acid and oleiins is then treated at a temperatureof about 180-210 F.'to polymerize the oleflns to diisobutylene. Thedi-isobutylene is then reacted with iso-butane in the presence of about90-100% concentration sulfuric acid to form iso-octane.

The following example will illustrate the conoctane in accordance withthe present invention. The di-isobutylene was obtained from selectivepolymerization of an unsaturated C4 petroleum fraction.

The di-isobutylene fraction (98.5% boiling between 90-125" C.) andlac-butane in the ratio of 1.35 mols of di-isobutylene to.5.22 mols ofisobutane were reacted in the presence of sulfuric acid of about 94%,H1304 concentration. The amount of acid used was about 1 parts of acidto one part of the hydrocarbons; The 'di-isobutylene fraction wasgradually fed into the mixture of the acid and iso-butane duringagitation, allowing a reaction time after addition of the diisobutyleneof about one hour. The temperature was maintained at about 87-93" F. andthe pressure about 30-45 lbs. gauge. The yield of isooctanewas about165% by volume of di-isobutene charged. The 'unreacted iso-butane,approximately 2.50 mols, was recovered, showing approximatelytheoretical conversion of di-isobutylene and iso-butane to iso-octane.Approximately by volume of the product distilled up to 257 F., about 18%distilled from 257-374" F'., about 4% from 374-410 F. and 2.2% above 410F. The octane value of the fraction boiling up to 257 F. was about andthe unsaturation of the fraction less than one per cent.

The above example is merely illustrative. It is contemplated thatdi-isobutylene from any source may be used for reacting with theisobutane. Also it is contemplated that other dibutylenes or octylenefractions may be used. For example, mixed octenes resulting from crosspolymerization of iso-butene with normal butene, or mixtures of normaloctenes and iso-octenes resulting from the polymerization of C4fractions under more drastic conditions or with less selective catalystsmay be-used. In general, higher temperatures, stronger acid, orincreased time of reaction than that required to produce relatively pureiso-octene, will produce-mixtures, and in case of stepwisepolymerization, the normal, octenes may .be produced from the unreactedproducts after removal of the tertiary olefins, by

The temperature and pressure may vary/f Temperatures of IO-90 F. arepreferred, al-

though temperatures as low as zero or below may version ofdi-isobutyiene and iso-butane to isobe used. In some cases it may 'bedesirable to use temperatures as high as 100 F. or higher.

The pressure need only be that necessary to maintain the products in theliquid phase. The. time of reaction will vary with the temperature andusually runsfrom'30 minutes to 2 or 3 hours.

While we have described a batch operation, it is contemplated that theprocess may be operated continuously by feeding the olefins and acid toa reaction coil, or chamber, from which reaction products are withdrawn.It' is desirable in a continuousoperation to maintain the reactionproducts of acid and olefins, or alkyl esters, at a low concentration.

Obviously many modifications and variations of the invention, ashereinbefore set forth, may be made without departing from the spiritand scope thereof and therefore only such limitations should be imposedas are indicated in the appended claims.

ewe claim? I 1. A process for the manufacture of normally liquidhydrocarbons boiling within the gasoline boiling range, which comprisesreacting low bolllng polymers, resulting from polymerization of Clolefins, with an isoparaflln selected from the group consisting ofisobutane and isopentane in the presence of concentrated sulfuric acidcatalyst, and maintaining throughout the entire reaction a substantialexcess of. the isoparailln in the reacting mixture, whereby alkylationof the isoparaflln is effected and a substantially saturated liquidreaction product is produced.

2.'A process in accordance with claim 1 in which the sulfuric acidemployed is in excess of concentration.

3. A processin accordance with claim 1 in which the reacting mixture ismaintained substantlally in liquid phase.

4. A process in accordance with claim 1 in which the low-boilingpolymers comprise di-isobutylene. l

5. A process in accordance with claim 1 in whichthe low-boiling polymerscomprise mixed octenes resulting from cross-polymerization ofisobutylene with a normal butene.

6. A process in accordance with'claim 1 in which the low-boilingpolymers comprise normal octenes resulting from polymerization of normalbutenes essentially free from isobutylene.

7. A process for the manufacture of normally liquid hydrocarbons boilingwithin the gasoline boiling range, which comprises reacting a lowboilingpolymer, resulting from polymerization of a C4 olefin, with a.low-boiling isoparafiin in the presence of strong sulfuric acid catalystof alkylation strength, maintaining throughout the reaction asubstantial molar excess of isoparaffin over the stoichiometricalequivalent mono meric contents of the olefin, and maintaining the alkylester reaction product of acid and olefin at a low concentration wherebyalkylation of the isoparaffin with the olefin polymer is effected.

KARL KORPI.

ARTHUR R. GOLDSBY.

